These days, a number of detection and analysis methods for determining physiological parameters in body fluid samples or other biological samples are performed in an automated manner and in large numbers in automatic analysis devices, also so-called in vitro diagnostic systems.
Current analysis devices are able to perform a multiplicity of detection reactions and analyses using a sample. In order to be able to perform a multiplicity of examinations in an automated manner, various apparatuses for the spatial transfer of measurement cells, reaction containers and reagent containers are required, such as, e.g., transfer arms with a gripper function, transport belts or rotatable transport wheels, and apparatuses for transferring liquids, such as, e.g., pipetting apparatuses. For samples, reagents, and also for the actual detection reaction, use is made of suitable vessels, which are also referred to as cuvettes. These usually comprise a closed wall and a possibly sealable opening for holding the respective liquid to be analyzed. The machines comprise a control unit which, by means of appropriate software, is able to largely independently plan and work through the work steps for the desired analyses.
Many of the analysis methods used in such analysis devices with automated operation are based on optical processes. These methods facilitate the qualitative and quantitative detection of analytes, i.e., the substances to be detected or to be determined in samples. The determination of clinically relevant parameters, such as, e.g., the concentration or activity of an analyte, is often implemented by virtue of part of a sample being mixed with one or more test reagents in a reaction vessel, which can also be the measurement cell, as a result of which, for example, a biochemical reaction or a specific binding reaction is initiated, bringing about a measurable change in an optical or other physical property of the test mix.
In current automatically operating analyzers, which are used for examining biological bodily fluids, the required reagents may be filled into a measurement cuvette by means of a pipetting apparatus with a pipetting needle. Here, with a cuvette gripper, the measurement cuvette is automatically displaced to different positions within the automated analysis machine by means of a robotic arm which is part of a robotic station. After the measurement, the used measurement cuvette is brought through a refuse chute in a refuse container for disposal purposes. A sensor may be provided on the cuvette gripper and/or on the robotic arm, with the aid of which force effects on the cuvette gripper or measurement cuvette may be measured.
When assembling an automatically operating analyzer, there always is a certain amount of uncertainty with respect to the positioning of, in particular, the robotic arms and other transfer and positioning systems. However, since these require exact positioning data for the automated procedure and exact cooperation, an exact adjustment is necessary. It may be carried out either manually with the aid of adjustment marks, highly precisely manufactured adjustment tools and/or automatically.
Usually, for the purposes of the automated adjustment, an appropriate sensor is initially present at the drive of the respective movable element of the transfer system to be adjusted, e.g., at a part of a transfer arm, said sensor forwarding information about the current position of the drive to the control unit. The transfer arm is then controlled by the control unit and moved toward a specific adjustment mark which, for example, is fixedly installed in the machine. Known adjustment systems often operate on a capacitive basis, with a needle, as a contact element, at the movable element being guided to a small metal surface at the adjustment mark. When contact is identified, the control unit stores the associated position of the drive. In other known adjustment systems, the contact element is arranged at the movable element by means of a hinge element, the hinge element having a self-restoring configuration, and a distance measuring sensor being assigned to a distance between the contact element and movable element.
Then, further assemblies in the machine, such as, e.g., receiving positions for liquid vessels, are arranged accordingly relative to the position of the adjustment mark. Ultimately, the transfer systems and the receiving positions must be adjusted correspondingly precisely relative to one another so that, e.g., liquid vessels may be transferred from a receiving position on one assembly to another receiving position on another assembly. In this case, attaching the adjustment mark and measuring the position of the adjustment mark relative to the position of, e.g., receiving positions may require much time and cost outlay and may be susceptible to errors. Furthermore, there may be changes in the relative position of the adjustment mark and the receiving positions during the operation of the machine, which may render a renewed, complicated adjustment and measurement of the machine necessary.